One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10)(11,16)(12,18)(13,22)(14,19)(15,17)(20,23)(21,24)(25,26,31,35)(27,32,38,40)(28,33,36,37)(29,34,39,30)(1,2,5,6)(3,7,4,8)(9,11,15,20)(10,16,17,23)(12,19,22,24)(13,21,18,14)(25,27)(26,32)(28,39)(29,36)(30,33)(31,38)(34,37)(35,40)(10,17)(11,20)(12,22)(14,21)(25,28,31,36)(26,33,35,37)(27,29,38,39)(30,32,34,40)(9,12,15,22)(10,18,17,13)(11,19,20,24)(14,23,21,16)(25,27)(26,32)(28,29)(30,37)(31,38)(33,34)(35,40)(36,39)(1,3,5,4)(2,7,6,8)(9,13,15,18)(10,12,17,22)(11,21,20,14)(16,19,23,24)(25,29)(26,34)(27,36)(28,38)(30,35)(31,39)(32,37)(33,40)(1,4,5,3)(2,8,6,7)(9,14,15,21)(10,19,17,24)(11,18,20,13)(12,23,22,16)(25,30,31,34)(26,29,35,39)(27,37,38,33)(28,40,36,32)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.